1. Related Patents
This patent application is related to my previously issued U.S. Pat. No. 5,813,184 for HEATED SERIALLY CONNECTABLE ROOFING SHINGLES, issued Sep. 29, 1998 which is hereby incorporated by reference.
2. Field of the Invention
The present invention relates to electrically heated roofing shingles. More particularly, the invention provides an improved way for supplying electrical power to electrically heated roofing shingles which facilitate rapid installation and reliable operation of the shingles.
3. Description of the Prior Art
Buildings having pitched roofs and located in areas of high snowfall are susceptible to damage occurring from accumulated snow or other frozen precipitation on their roofs. Thermal expansion and contraction of ice caused by temperature changes may cause physical damage to the roof surface itself or to underlying structural elements. More importantly, however, is the damage caused by infiltration of water resulting from melting of snow and/or ice which backs up under the snow pack on the building roof behind ice dams near the eves of the building.
It is common in northern regions to attempt to abate these problems by installing heating elements such as heating cables or tapes directly on top of the roof. These solutions have, by and large, been only moderately successful. Several heating devices specifically designed for combating the specific problems facing shingled roofs have also been proposed.
One solution is described in U.S. Pat. No. 2,699,484 for DEICER FOR ROOFS, issued Jan. 11, 1955 to H. L. Michaels. MICHAELS teaches a heating devices intended for installation along the lowest edge of a roof. Unlike the roof heating system of the present invention, the MICHAELS system provides heat only along a narrow band near the edge of the roof. These types of solutions are generally considered ineffectual in preventing ice damage and water infiltration. The inventive system, using heated roofing shingles, provides heat for several courses of shingles up the roof which is very effective in preventing problems caused by ice dams near or at the edge of the roof.
Two patents, U.S. Pat. No. 3,691,343 for MODULAR SYSTEM OF ROOF HEATER SHINGLES, issued Sep. 12, 1972 to Victor B. Norman and U.S. Pat. No. 3,129,316 for HEATING ELEMENT FOR ELIMINATING ICE FROM A ROOF, issued Apr. 14, 1964 to F. N. Glass, et al. teach shingle-like heating elements for installation along the lowest edge of a building roof. While these kinds of solutions typically are more effective than that of MICHAELS, in that they heat a larger surface of the roof, they still fall short of the effectiveness of the inventive system. The system of the present invention allows a varying number of courses of heated shingles to be applied, the number of courses being selected based on the environment, the roof pitch, etc.
U.S. Pat. No. 2,546,743 for ELECTRICALLY HEATED DEICING SHINGLE, issued Mar. 27, 1952 to J. L. Harrison teaches a conventional style roofing shingle having an embedded resistance heating element. Each shingle must be individually connected to a power line running above and along the long axis of the course of singles. Installation requires that two electrical connections per shingle be made in situ thus requiring a competent, usually licensed electrician as well as a roofer to complete the installation. Because of the environment, each connection is subject to thermal stress which may result in electrical connection failure during the operating lifetime of the roof. The inventive heated roofing system, on the other hand, utilizes high-reliability, slip-on connectors on each shingle adapted to interact with mating connectors on a pre-assembled, flat power cord. The roofer may then both physically install the shingles and easily and competently make the electrical connections between the shingle and the power line.
Finally, U.S. Pat. No. 5,813,184 for HEATED, SERIALLY CONNECTABLE ROOFING SHINGLES, issued Sep. 29, 1998 to the Applicant, teaches heated roofing shingles having electrical connectors disposed on extended tabs at each edge of the shingles. During installation, the connector on the abutted edges of adjacent shingles readily connect to one another thereby establishing a serial connection across the width of the roof. While the system is easy to install and the electrical connections provided have proven to be reliable, the performance of the roof heating varies as the number of shingles in the serial chain varies. The system of the instant invention overcomes this situation by providing a parallel electrical connection to each shingle. The ease of installation is maintained by providing a pre-assembled, flat power cord having slide-on connectors space periodically along its length offering a connection point for each shingle.
None of the above inventions and patents, taken either singly or in combination, is, however, seen to anticipate or suggest the instant invention as claimed.